Iron is an essential element in maintaining normal structure and functions of the central nervous system. Dangerous effects of decreases in the bioavailability of iron in the brain are shown to affect brain biochemistry, neurotransmitters production and function, mainly in the dopamine-opiate systems well as cognitive functions (learning and memory) and a number of physiological variables such motor activity and thermoregulation. Recent research has shown the added complications and deficits that are introduced in the endocrine and the immune system activity. While iron deficiency is not perceived as a life threatening disorder, it is the most prevalent nutritional disorder in the world and a better understanding of the modes and sites of action, can help devise better treatment programs for those who suffer from it.